The interfacial processes at polymer-modified electrodes are investigated using electrochemical impedance and color impedance (electromodulated optical transmittance) spectroscopies. Direct in situ evidence for faradaic charge transfer with double-layer charging is obtained for polypyrrole/polystyrenwulfonate (PPy/PSS - ) composite films in 1 M aqueous LiCl, NaCl, KCl, CsCl, and Me 4 NCl. On the other hand, the high-frequency charging is found to be coupled with adsorption-related (faradaic) charging for the film in 1 M aqueous Bu 4 NCl. Thwe results are modeled with an equivalent circuit taking into account both the double-layer and adsorption-related capacitances at the film/solution interface